Printing telegraph system and apparatus



Jan. 6, 1942. R. E.'ZENNER PRINTING TELEGRAPH SYSTEM AND APPARATUS Filed May 23, 1938 2 Sheets-Sheet 1 FIG. 1

Jan. 6, 1942. R, E EN ER 2,268,631

' .PRINTING TELEGRAPH SYSTEM AND APPARATUS Filed May 23, 1938 2 Sheets-Sheet 2 7 FIG 207 O /2o5 213 K x @215 66 2' 2 20 a INVENTOR.

2|4 K 2" RAYMOND E. ZENNER A ORNEY- line.

Patented Jan. 6, 19425.

f PRINTING TELEGRAPH SYSTEM AND APPARATUS Raymond Zenner, Chicago,

Teletype Corporation,

tion of Delaware I Application May 23, ms, Serial No. 209,523

19, Claims.

This invention pertains to systems and more particularly to telegraph systems and apparatus adapted to be operated intermittently under the control of records in a control strip. 1

In telegraph systems involving apparatus for recording characters by a series of elemental areas of positive and negative surfaces, transmitting apparatus has been employed wherein each letter, symbol, or character is analyzed into a succession of constituent areas and a code set of corresponding character embodiments are constructed, which embodiments then are selected under control of a message record tape. In accordance with such scanned or analyzed embodiments. electrical impulses are generated which cause corresponding operation of recording ap- Daratus of the formv disclosed in United States Patent No. 2,131,741 to form the characters in a An important object of the present invention 111., assignor to Chicago, 111., a corpora- (oi. Ira-:4)

printing telegraph is to control automatically the cessation oi transmission of signals from a tapecontrolled transmitting mechanism in response to a taut condi-i tion of the tape and to provide for resumption of transmission only in response to manual control.

Another object of the present invention is to provide an arrangement for invariably supplying to a transmission channel a start-condition automatically upon a resumption of message transmission to assure that tape feeding will start in the printer when the transmitter is started and before message matter is transmitted.

In accordance with a feature of the invention a means is provided in an intermittently operating system for transmitting the start signal invariably when transmission is resumed after a cessation thereof to avoid the necessity as in synchronous systems of moving or feeding the receiving and recording tape continually.

.A feature of the invention is directed to the tape control circuit for telegraph printers where by the tape is caused to move continuously only during the time when messages are being recorded.

A further feature pertains to printing on waxed paper by arcing between the scanning wheel and a. knife-edge platen.

Another feature of the invention pertains to means for assuring the distinct printing of characters by eliminating rebound of the printing hammer.

The above and other objects of the invention are achieved through the provision of a mechain accordance with a five-unit orfBau'dot code which, through its electrical contacts, controls the energization of a plurality of electromagnets one individual to each element of the code. These electromagnets serve to control latches individual to each of a plurality of permutation bars. "The permutation bars-are thus set, in accordance with the energization'of the electromagnets and in accordancewiththe code combination appearing in theperforated tape, to select one pair of a plurality of pairs of brushes. Individual to each pair of brushes is a pair of code discs designed in accordance with a method oi p'rescanning in which the characters or symbols to be transmitted are divided into'any desirable number of sending units or areas. 'The' several unit areas thus createdare assigned in order of scanning to the periphery of the code discs. -Specifical1y,the two discs constituting a pair of code discs are allocated to letters and figures or upper and lower case characters, re; spectively. Withthe selection and cooperation of a pair of brushes with a 'pair of code discs, it

is necessary to select between code discs' of the pair. To accomplish such a result, mechanism responsive toshift andunshift signals appearing in the perforated tape is provided to select benism for sensing perforations in a tape perforated selecting between the tween a 'pair of collector rings, one identified with theshift signal and the other identified with the unshift signal. Under such circumstances, one discof each of the pairs of discs will be connected' to one of the collector rings, whereas the other disc of each of the pairs of discs will be connected to the other collector ring and by collector rin s in accordance with the shift and unshift signal combinations, the individual disc'indicative of the char- 1 acter to be transmittedcan be selectively determined. Inasmuch as the code discs rotate continuously by power communicated thereto froma continuously rotatingfrnotor and the brushes are selectively operated .in accordance with the permutative setting of the permutation bars, impulses representative of the positive and negative surfaces of the character code disc will be transmitted-which will be eifective at the receiving end of the system to record a character in accordance with the pattern of the character. formed on the peripheryof the code disc then -efie'ctive for the transmission ofthe characteristic impulses.

As previously indicated, the code discs rotate continuously, and further, the permutation bars are set in response to the energization of electro magnets-controlled by a tape sensing mechanism ments of the sensing mechanism. Under cer--' tain conditions, it is desired to arrest the oper-la ation of the transmitter or the tape sensing mechanism and therefore mechanismis provided;

for locking the tape sensing elementsin their withdrawn position, notwithstanding the fact --as fu lly,described in the aforementioned patent.

The several unit areas thus created are assigned in order of scanning to the periphery of each of. the'discs i2,'the dark areas of a signal or message being the high surfaces ll to engage that the control cam and the code continue to rotate. Such a result is accomplished through.20

the provision of a contact operated by a tauttape switch arm which, when opened, causes the de-energization of a relay of the circuit; to 88118.1).- lish a condition to energize a control relay which, in return, controls the energization of a locking magnet of the tape sensing mechanism to render it inefle'ctive, notwithstanding the fact that the operating magnet of the 'tapesensing mechanism continues to be energizedonce for each-cycle of rotation of the code discs and their associated control cams. When the operation of the transmitter is thus arrested, it causes the movement of the tape at the printer to' be arrested byv controlling the release of the tape stop z, nagnet ar maturedue'to the presence of spacingcurrent onthesignalline'. I, Further control means is provided according to the present invention to insert automatically, upon restarting the transmitter by closing the contact operated b t e taut-tape switch arm, ,a start signal which 'acts to operate the-tape stop magnet, which, upon re--energization, acts toinif tiate the movement. ,of the tape at theprinter preparatory to resumption ofv message transmission and reception. v, v The invention. will be explained hereinafter more fully with reference to the-accompanying drawings, of'which I I Fig. 1 shows schematically the tape sensing mechanism and the elements of the distributor through which the electrical impulses indicative of the characters are transmitted;

Fig. 2 shows diagrammatically elements transmitter;

Fig. 3 is a'schematic viewof a receiver, circuit embodying a tape stop control arran ement;

Figs.'4, 5 and 6 represent modified tape stop control arrangements; l

Fig. '1 is a schematic view of a receiving circuit for printing on chemically prepared paper by means of arcing; and

line coil and platen shownin Figs. 3' to 6.

of the,

Referring now to the drawings, particularly:

Fig. 2, it is noted that shaft Ihassecured there-Q to a pinion gear I which meshes with a worm gear 9 driven by power communicated from acontinuously operating motor, it. The, relation. between gears 8 and 8 is such as to cause rota tion of shaft 1 at a speed calculated to effect the accurate and proper distribution of current'impulses indicative of the characters to be trans mitted. Secured also to shaft 1 are a plurality of code signal discs 12, each forming a trans.

mitting element, or character member, symbol a brush designed to cooperate therewith to send a--signal. =It-.-is, of course, obvious that the depressed or reduced or insulated portions of the codediscs I! represent the light areas of the signal or message unit. Obviously thelight areas might bemade the high surfaces, depending upon the preferred method of transmission.

The :term mechanical prescanning refers to the analysis of a character into the signals suitable for transmission and comparable to the seaming of, the character. The production of the mechanicalmember or disc containing elements thereby corresponds directly and individually to the. signals and represents individual characters. For example, a character or letter may be prescannedbydividing its total area into a plurality -of,unit areas arranged in a predetermined number of vertical strips with a predetermined number of units within each strip. The character is .thus divided into a plurality of strips laid off in a predetermined number of equal angular sectors on the code signal disc I! and each angular-sector is-divided into a predetermined number of angular units, each corresponding to a unit area of. the corresponding vertical strip. The periphery .of the code disc I! is then executed ,by recessing the corresponding disc unit sectionsof. each sector where the respective unit areasare-light, and where the units are dark,

'raised. surface; 14 remain. With such a plan,

. co- Fig. 8 is an enlarged cross sectional view .of the eachof thecode discs I2 is correspondingly developed.

7 From the foregoing explanation of the arrangement of the code discs I2, it is evident that thepresent invention contemplates a code disc for each character or symbol to be transmitted; that is, there will be a code disc I2 individual to each-letter of the alphabet and each numeral and other special characters. These code discs. being secured to but insulated from shaft I, will rotate therewith continuously, .and during their "rotation, provided a selection has been established, will effect the transmission of signal impulses indicative of its character.

The discs i2=are arranged in pairs and being so arranged, it is necessary to interconnect a disco! each pair which, in turn, are connected to a collector ring I! which is also secured to shaft'l. Likewise, the, other code disc of each of the pairs of code discs are interconnected and, in turn, are connected to a collector ring 'II which, as noted for collector ring I5, is also securedto-shaft 1. Interconnection of the several code discs. with the collector rings II and i6, respectively, ,is achieved through the provision of coiled conductor springs l1 and I8. The coiled springs i1 and are compressed between corresponding ones of the pairs of code discs I! or physicalembodiment of a symbol.- Thesecode-" and-are-insulated from the intermediate code mam mined signaling condition and through their operation with brushes individual thereto, to transmit a start signal at the beginningof each resumption of message transmission, as will be explained hereinafter.

In the operation of the transmitter certain functional operations are performed by cams 22, 23, and 25 secured to shaft 1. The noted cams are positioned on shaft 1 with respect to each other and with respect to code discs 12 to perform their respective functions in timed rela--" tion with the other functional responses and'the transmission of signal impulses from the code discs 12. It is obvious, therefore, that the cams 22, 23, and 25 may be oriented on shaft 1 with respect to each other to provide proper sequential operation in a manner fully contemplated by the present invention.

Positioned below the shaft 1 and the code discs I 2 are a plurality of permutation bars 21, 28, 29, 30, and 3!, or one individual to each element of the code. According to the embodiment of the invention disclosed in the aforementioned drawings, a five-unit code is employed. Accordingly, there are five permutation bars or one in-- dividual to each element or unit of the code. Operation of the permutation bars is attained through the arrangement of an electromagnet individual to each of the bars. Under such circumstances there are five electromagnets ,35, 30, '21, 38, and 39. These electromagnets are selectively controlled from a tape sensing mechanism 45 and each controls, through its armature,a spring-held latch 42 which engages ashoulder formed on the upper edge of its permutation bar to hold it against the action of its spring 48, there'being a spring 43 individual to each of the permutation bars. Under such circumstances, when an electromagnet is energized, the' spring loaded latch 42 is operated to move its with stationary contacts 54 to .eifect a circuit closure andfcause the energization of the electromagnet connected thereto; since the contact springs 52 areconnected through their individual springs 55 to a p sltive bus bar56.

.Assume, for; example, that a sensing finger 48 encoimters' a ,nerforated area in tape 5l.

Through its 'contact spring 53,, engagement will beimade with its stationary contact 54 and an energizing circuitfor theelectromagnet 35-3! connected thereto will be established. The electroma'gnet will be eme'rgized,and latch 42 will be operated-against the action of'its spring to free a the permutation bar individual thereto. for action by its spingf-fl'. Such permutation-bar will be moved to 'thele'ftas'viewed.inFig.1.;

Under"certain]..conditionsflof operation, it is desirable topreventthe.operationlof the" tape end free of the projection on the, upper edge of its permutation bar, whereupon such permutation bar is moved to the left, as viewed in Fig. l, by the action of spring 43. H

The tape sensing mechanism 40, as is fully and completely disclosed in U. S. Patent No.

1,460,357 embodies a plurality of tape sensingfingers which serve tosense preforations in tape 58 which has been perforated through 5 the,

operation of a keyboard perforator to form transverse rows of code perforations indicative of the characters or symbols of the message to be transmitted through the effectiveness of code discs l2. As is fully disclosed in said Patent No. 1,460,357flthe sensing fingers 45 are pivoted on a rod 5| and are movable about such rod by an electromagnet 52. Specifically, electromagnet 52, upon being energized, .draws its magnetic yoke to shift its cores axially to push a nonmagnetic pivoted plate 51 against the five tape sensing fingers 46 and thus withdraws the sensing fingers 46 from engagement with the perforations in the tape 50 and causes,'following such withdrawal, the advancement of the tape through a ratchet and pawl mechanism (not shown) to present the next transverse row of perforations in alignment with the withdrawn ends of the sensing fingers 46. v

Attached to and operated by each of the sensing fingers 48 is a contact spring 53. There being five sensing fingers 46, there are five con- "sensing" fingers "44," notwithstanding the" fact that the 'electromagnet'52.is.-energized'cyclically. In

order to. achieve such a resultjan electromagnet" 58 havingan armature 551s provided. Through its armature, electromagnetic lock -the pivoted plate of electromasnet u e that, notwithstanding the fac'tjthat the electromagnet 52 is eners edf cyclicallyifitfiwill have. no functionairesponse'on fingers, its cores merely engaging. .the3-jpivoted plate 1 51 :held fixed by armature 55., a

Asshown 1 theflower of r the permutation'bars -21.' 3 fl..ig fonntdwith a plurality of notches; arranged permutably'so that upon the permuted operation of electromagnets 35-89, corresponding operation ofthe permutar I tionibars, 21-" will result in' the alignment-0f the notches ".to'effect theselection of one of a plurality of selectable bars 53. There is aselectable bar 58 individual toeach pairfof code signal discs l2. Each selectable, barjsisindividual to a brush carrierorsupport 64 'pivoted on lot! 55. The brushsupports 6 4 cari 'yla pair of brushes 45, and 51 individual to .res'pective code signal discs i2 constituting a .naii'gqf code, 8 al discs.

Each ofthe bmsh suppbrtsju has a downwardly projecting portion. which liesin the path of its individual selectable'bar 6.3, 'so that upon the operation of selectable bar 53,: brush support 54 will be rotated .in'a' clockwise direction abcutrod 65, as viewedini'ig. 2, against the action of its retractile spring 59 provided, however, that the brush support 84 is at that instant free to move. As shownin Fig. 2, the brush support 54 has an'extension 14 arrangedwith its end-formed in a knife-like fashion to cooperate with a correspondingly shaped ball 11 which is pivoted on rod 12. and which is operated by cam 22against the tension of a spring 13 to free, through its disassociation with extension 10, brush support 64 for operation. Release of extension 10 ofbrush support 04, as will of course be recognized, occurs in timed relation with respect to the other functional responses of the.

rotation of shaft 1, cam 23 is eflective ior operating lever 11 to move selectable members 53 counterclockwise about their pivot- 45 against --the action .of their retractile springs .85, there being a retractile spring 84 individual to each t ct springs 53. Contact sp in newer? or the selectable members 88. With the selectable members it moved counterclockwise, as viewed in Fig. 2, and out of engagement with permutation bar's 21-81, the permutation bars are free to be moved under the control of electromagnets 35-88 in response to the operation of the tape sensing fingers 48.

when the permutation bars 21-4l are positioned in various combinations in response to I. the permuted energization of the electromagnets to the left and others intheir normal unactuated position. Following the setting of the brush support 68, the locking ball TI is restored by its spring 18 to a position where it engages extension 18 and holds'the brush support 84 in its set position. The selectable member 83 is thereupo'n free to be restored toits normal position out of cooperation with the permutation barsv 21A! and thus the permutation bars may be reset to select either the same selectable member 88 or another selectable member 88 identified with a'dlfferent pair of characters. With such an arrangement it is possible to initiate a selection during the interval the brushes 86 and G1 are in engagement with the code disc i2 101' the transmission of signal impulses characteristic of their. peripheral formations. Such an arrangement has been referred to as an overlap, since it makes possible a selection during the period impulses are beingtransmitted for a previous character selection.

Following the selection of a selectable bar 3 and the operation of a brush support 84, a cam (not shown) becomes effective to restore any of the permutation bars 213|, previously moved to the left as a result of the energization of the electromagnets 8588, to a position where the latches 42 are effective to hold the permutation bars against the action of their springs 88. Cyclically, therefore, with respect to the rotation of shaft I, the permutation bars 21- will be restored to their normal or unactuated position.

As previously described, a code disc I! of each pair of code discs is connected to collector rings .II and It, respectively. Continuously in engagement with each of these rings is a brush 84 and 85 (Fig. 1), respectively. These brushes are eflected. The selection and operation of the selectable bars 88 and 84, which are identified with ligures'and letters or shift and unshlft signal combinations. respectively, are selected and operated through the setting of the permutation bars 21---8| in response to the energization of the electromagnets 8588 for the signal combinations identified with figures and letters, re-

spectively; that is, when a transverse row of periorations in tape 88 for figures is sensed by mechanism 48, the tape feelers 86 are operated correspondingly and the contact members 83 will be operated to cause the energization of certain of the electromagnets 85-38 to set permutation bars 21-81 to align their notches to select and permit the operation of selectable bar 83. Under such conditions of operation, member 88 will be moved tothe right through the rotation of bell crank lever 88 in a counterclockwise direction to cause the engagement of contactor 88 with contact 81. Inasmuch as contactor 88 was previously in engagement with contact 86 and since the contacts 88 and 81 are connected to collector rings l8 and I8, respectively, the circuit will be changed from collector ring l5 to collector ring it. correspondingly, selectable bar 88 may .be operated in response to 8. letters code combination in tape 50 to cause the member 88 to move connected through electrical conductors to contacts 88 and 81, respectively. Cooperating with these contacts is a contactor 88 pivoted at one end and engaged at its other end by a rockable member 89. Secured to member 88 are two oppositely arranged bell crank levers and 8|, arranged to move member 88 either to the right or left, depending upon whether bell crank lever 88 or hell crank lever 51 is operated to cause corresponding movement of contactor 88 to engage either contact 86 or contact 81.

Operation of hell crank levers 80 and 9| is achieved through selectable bars individual thereto. As shown, in Fig. 1, selectable bar 83 is individual to hell crank lever 80, while selectable bar 88 is individual to hell crank lever 9|. Upon the selection and operation of either of the selectable bars 88 or 88, the bell crank lever 88 or 8| individual thereto will be operated and corresponding movement or member 88 will be contactor 88 from engagement with contact 81 to engagement with contact 86.

Inasmuch as a code disc of each pair of code discs is connected either to collector ring I! or collector ring l6 and since the circuit from the depend upon the position of contactor 88 which,

as shown in Fig.1, is connected to a radio frequency' transmitter 85 which may be of any design. Oi course, instead of employing a radio transmitter, operation of the system according to the present invention over land wire lines by direct current or. carrier current signals is also feasible. I

' Positioned near the entrance end of the tape senser 48 is a mechanism commonly referred to as a taut-tape switch mechanism which responds to the-tape to exercise control functions. Such a mechanism, as exemplified in Fig. 1, embodies a bracket 88 to which is pivoted an arm 81 extending transversely of and adapted to be engaged by the tape 50. Cooperating with arm 81 is a lever 88 which is also pivoted to bracket 86 and which is urged to the right, as viewed in Fig. 1, by a spring 88. Lever 98 has two notches, one arranged to hold the arm 81 in a horizontal plane with respect to the movement of tape 50, and the other serving to hold the arm 81 in a tilted or latched position. Cooperatlng with lever 88 are contacts I00 which are included, through a manually operable switch I01, in circuit through the upper armature and back contact of a relay I82 with the winding of electromagnet 88.

Under operating conditions, electromagnet I8! is normally energized and has its locking circuit controlled by contacts I00. When the tape 88 becomes taut, arm 8'! is rotated in a counterclockwisedirection and thus allows lever 88 to move to the right. as viewed in Flg. 1, under the action of spring 98. In so moving. lever 88 opens contacts I00 through which the locking circuit of relay I82 is interrupted. Due to the notch arrangement of lever 88, arm 81 is retained in the position to which is was moved by the action of tape 88, where lt remains until lever 88 is I 2,268,68i. restored manually to the position shown in Fig. 1.;

The receiving printer, represented diagrammatically in Figs. 3 to 6 and with which the transmitting apparatus exemplified by Figs. 1 and 2 cooperates, is normally operative, with its printing or recording wheel constantly rotating. However, the recording medium or tape is normally arrested during cessation of message transmission and reception, but upon receipt of the start' condition controlled by code discs I9 orv 20, as will presently appear, the tape movement is initiated and continues without the exercise of fur-' ther control from discs I8 or 20.

Normally, with characters like B, D, H, N,fetc., which begin with a vertical stroke, indicative of a prolonged marking condition, the movement of the tape would be initiated automatically upon resumption of message transmission, butwith characters like C,-G,.O, S, V, etc., which do not begin with a vertical stroke, the tape control mechanism at the receiving end, which responds to a long marking impulse for initiation of message transmission, will not, when one of the last noted characters is the first character to be received upon resumption of message transmission,

, respond at the proper time to efiect initiationv oi the movement of the tape due to the absence of a long marking impulse. To supply this long impulse invariably upon the resumptionmessage transmission, the code discs I8. and 20 are provided and are selected for operation in the following manner. a

The starting condition is established through closure of switch IOI and I00 concurrently. Up-

on the closure of the switches, a circuit is established extending from grounded battery, through the closed contacts I00, the contacts of I switch III, the upper armature and back contact of de-energized relay I02 and the winding of se-; lector electromagnet 00 to ground. a magnet 30 is thereupon energized and acts through a bell crank 02 to unlatch the permutation bar 00 which, in turn, is actuated by its spring 43 to its leftward position to produce a setting of the permutation bars'to permit the selection of a selectable bar 63 identified with brush carrier I05 (Fig. 2) which, upon being operated and held in its operated position by bailll, causes its brushes to engage contact dilca I0 and 20. The periphery of these" contaet discs is formed such as to effect the transmission of a prolonged marking signal which functions as a start signal, the circuit. of which maybe traced from grounded battery connected tobrush support I05, through either disc I0 or 20 (depending upon the position of contactor 08) Selector ductor I01, and the winding of relay I02 to ground. Relay I02, upon being energized, establishes its locking circuit extending from grounded battery through contacts I00 now. closed, contacts of switch IOI, armature and front contact and winding of relay I02 to ground. Relay I02 thus is maintained energized as long as contacts I00 and the contacts of switch IOI are closed.

The closure of contacts I06 is momentary.- Contacts I06 open when brush I05 drops out of selection due to the change in the setting of code bars 63 brought about by opening the upper con tact of relay I02 when relay I02 is energized upon closure of contact I06.- Selector magnet 36 is thereafter under the control of the tape sensing mechanism.

Upon the energization of will be completed upon the closure of contacts I00'under the control of cam 25. As previously described, cam is efiective cyclically with respect to the other cams secured to shaft I and the code signal discs I2 also secured to shaft I, so that for each cycle of rotation of shaft I, contacts I09 will be closed and with relay I02 energized, an energizing circuit will be corri-v pleted .for relay I00 extending from grounded 1 battery, through contacts I09, conductor IIO,

conductor III, lower front contact and armature of relay I02, and the winding of relay I00 to ground. Relay I00 is thereupon. energized and opens, through its back contact and armature, alocking circuit forrelay II2 which has its right-hand winding connected in series with the windings of electromagnet and which will thus be energized upon the completion of an energizing circuit including the right-hand winding of relay H2. 1

Also connected in circuit with contacts I00 are the windings of electromagnet 52. Therefore, upon the cyclic closure of contacts I09, a

circuit will be completed for the energization of.

electromagnet 52- which extends from grounded battery, through, contacts I09, conductor IIO, conductor III, conductor II3, and the winding of electromagnet 52 to ground. Electromagnet 02 will thereupon be energized for causing the retraction of tape feelers 46 and the advancement of tape 50 to present the succeeding transverse row of perforations in alignment with the tape feelers l0.'

The left-hand winding of relay I I2 is also controlled by contacts I00 and is energized mosprings ILpr I0, collector ring It or I0 (depending upon whether contactor 80 is in engagementwith contacts 00 or 01), to the input'side of the radio frequency transmitter '05. With reed to discs I0 and 20, it is noted that either of" these discs may be effective for the transmission of a start impulse, regardless of whether the transmitting apparatus was previouslyemployed for the transmission of either letters .or

figures combinations. Consequently, regardless of the previous position oi contactor 80, a start impulse will be.transmitted in response'to manual closure of switches I00 and IN. Q 7

Operated upon the selection and operation of .brush carrier I05 are contacts I00. These contacts are connected to thawindirig of relay I02 and upon their closure, cause the energization of relay I02 over a circuit extending from grounded battery through contacts I05, conmentarily upon the closure of such contacts to close the circuit including its right-hand winding and the windings of electromagnet 50. However, with relay I08 also energized, due to the fact that relay I02 is now energized, an energizingcircuitfor the windings of electromag net 50 is 'not completed' Assume, for the purpose of; illustration, thattape 50 becomes taut and further, thatarm "01 gized and its back contact will be closed so that upon the energizationof the left-hand winding of relay II2,- an energizingcircuit for its right.- hand winding or locking winding is completed relay I02, an ener-. gizing circuit for relay I00 is conditioned which 7 extending from grounded battery, conductor II4, back contact and armature of relay I88, armature and front contact of relay I I2, right-hand winding of relay II2, conductor H5, and the windings of electromagnet 58 to ground. Due to the establishment of such a circuit, relay II2 will be maintained energized and electromagnet 58 will be energized to hold, through its armature 59, the pivoted plate 51 of electromagnet 52 to hold the tape feelers 46 out of engagement with tape 50 and prevent the further advancement of the tape. Transmission under such conditions will be arrested. It is, of course, understood that the shaft 1 and its code discs, together with its cams, continues to rotate. Contacts I09 will be closed cyclically through the operation of cam 25 and current will be impressed upon the windings of 'electromagnet 52. but its energization will have no effect since electromagnet 58 is energized and the pivoted plate 51 is rendered inefiective.

To start transmission, notwithstanding the fact that tape 50 may have in the meantime become slack and a loop formed therein, it is necessary for an operator to restore manually lever 98 to the position shown in Fig. 1. Upon such restoration, contacts Ilill will be closed and a circuit will be established for electromagnet 34 through the energization of which, as previously described, brush support I05 will be selected and operated for the transmission through discs I8 and of a start impulse, contacts I88 will be closed, and an energizing circuit for relay I82 will be established.

When transmission of all messages has been completed, switch IIII may be opened and the result described for the opening of contacts IIIII will be effected.

The signals transmitted from the radio frequency transmitter 95 (Fig. 2) are received by the radio frequency receiver I20 (Fig. 3), where they are demodulated and amplified and are directed through a line coil I2I of a radio printing apparatus of the type shown in aforementioned Patent No. 2,131,741, thence to ground. These signals are also directed over conductor I22, through winding I23 of a double winding relay I24, and thence to the ground. The line coil I2I and the winding 23 are, accordingly, connected in parallel. The radio print-er disclosed schematically in Fig. 3 comprises the printing or recording wheel I which is normally rotating constantly. As disclosed in said copending application, printing or platen wheel I25 is provided on its cylindrical surface with symmetrical spiral knife edges I26 which cooperate with an operating member or platen I21, having a knife edge arranged transversely of the tape I28. Platen I21 moves with theline coil member I2 I and reciprocates vertically with the line coil in response to the received signals; Thus, in response to a marking signal the line coil will be actuated upwardly, bringing the platen against the printing wheel, then upon receipt of a spacing signal the coil moves downwardly under the action of gravity or by means of a return spring, bringing the platen against a down stop 22I (Fig. 8.) To prevent bouncing of the platen which occurs when the platen is rigidly secured to the line coil spool 222, thus causing undesirable I marks on the tape, especially when an inking roller is used, the construction shown in Fig. 8' is employed. With this arrangement, the platen 223 is fitted into a bushing 224 supported by the line coil sp'ool 222. The spool 222 is interposed between a pair of rubber washers 225, preferably of sponge rubber, which are clamped between a flange on the platen 223, and a metal washer 228, by a cotter pin 221. The rubber washers act to eliminate rebound because of the ability of rubber to absorb mechanical energy without releasing the same due to its high internal friction. Thus, when the assembled platen and line coil are actuated upwardly toward the printing wheel in response to a marking signal, the platen 223 strikes the printing wheel and tends to rebound, but due to the continued upward force of the line coil spool 222 the rebound of the platen is resisted, the rubber washers 225 serving to absorb the mechanical energy expended by both the platen and the line coil. The same result is achieved upon the return or downward movement of the assembled platen and line coil when the platen 223 impinges against the down stop 22I. With this arrangement distinct printing is assured. Obviously, any material having high internal friction mightbe used in place of rubber.

The line coil I2I is arranged over the core I28 of the local field magnet I3I and operates between the poles I32. The winding of the coil I3I is connected in an obvious circuit, such as is diagrammatically shown in Fig. 3. As fully described in the aforementioned Patent No. 2,183,741, the field coil I2I responds to marking signals to raisethe platen I21 against the tape I28, thus pressing the tape I28 and a contiguous strip of carbon paper against the spiral knife edges I26 of the rotating printing wheel I25, whereby the tape I28 is marked in accordance with the received marking signals to record characters. It is understood, of course, that an ink roller may be substituted for carbon paper. As contemplated by the present invention, the tape I28 moves only during signal reception and for a predetermined interval thereafter. and control means is provided to stop the tape after said predetermined cessation of message reception. For example, tape feeding continues for at least twenty-five character spaces after transmission and reception have ceased.

As previously mentioned. the signal impulses extend over conductor I22 through the winding I23 of the double winding relay I24. During signal reception, the received marking impulses cause the relay I24 to become energized. Upon energization, relay I24 attracts its armature I33 to close contact I 34, thereby establishing a looking circuit from positive battery, through a second winding I35 of relay I24, through contact I34 (now closed), armature I33, thence through .the windings of a stop magnet I36, through a contact I31, to ground. When this circuit is established, magnet I36 becomes energized and pulls up its armature I38. Armature I38 is provided with a stop lug I38 which cooperates with a projection I on the periphery of a stop disc I42 connected to a shaft I43 by means of a friction clutch (not shown).

Accordingly, in response to the first marking signal the double winding relay I24 will be energized to establish the energizing circuit abovedescribed for the stop magnet I36, which by attracting its armature I38 permits rotation of the stop disc I42 to be initiated. The stop disc I42 being operatively associated with the tape feed roller I44, thereby controls the initiation of movement of the tape I28.

As previously mentioned, to assure that the characters are properly recorded, a special starting impulse is transmitted upon the resumption of message transmission, so that when the character signals are received by the radio printer,.

the tape I28 will have been started in motion by the operation of magnet I36. The starting are being received.

The projection I, after being released by the armature I38, operates, after traveling a few degrees, to open the contact I31 to break the locking circuit previously described for magnet I36 and relay I24. In response to this condition, armature I33 is released and contact I34 is opened. Also, armature I38 is released to bring lug I39 thereon again into the path of the projection I of disc I42. A time interval corresponding to about twenty-five characters isrequired for the tape driving disc to reach the stop position after opening the contact I31; therefore, if there should occur a cessation of message reception longer than this interval, the movement of the tape I28 will be automatically arrested.

A modified form of automatic tape control is shown in Fig. 4. This arrangement is similar to the one shown in Fig. 3, the received impulses entering over the conductor II and dividing at I52 to pass through the line coil I53 and winding I54 of a double winding relay I55, the coil I53 and the winding I54 being connected in parallel. Like the arrangement in Fig. 3, the coil I53 and winding I54 respond to the marking impulses. The line coil I53 cooperates with the local field coil I56 to actuate platen I51 against the recording wheel I58 in the manner previously described in connection with Fig. 3. A start impulse will energize the winding I54 to attract the arma ture I59 to close the contact I6I to, complete an energizing circuit for magnet I62 from battery, through winding I63 of relay I55 over armature I59, through contact I6I, through the winding of magnet I62, through the closed contact I64to negative battery. The latter described circuit comprises a locking circuit for both the relay I55 and the magnet I62. Magnet I62 upon being energized attracts its armature I65 to release the stop disc I66 for rotation. rotating a few degrees acts to open the contact I64 to break the locking circuit for magnet I62 and relay I55, in the manner described in connection with Fig. 3. Therefore, if a marking sig-' nal is received at or before the time that the disc I66 is about to be stopped by the armature I65, the armature I65 will be actuated out of the path of disc I66 to permit it to continue its rotaion, thereby, in this manner imparting continuous movement to tape I61.

Another form of automatic tape control at the receiver is shown in Fig. 5. In this arrangement, the amplified signals enter at HI and extend through the line coil I12 to ground. The line coil acts in conjunction with the local field magnet I13 to reciprocate the platen I14 into operative engagement with the recording wheel I15 fixed to the shaft I16. Connected to the shaft I16, by means of a friction clutch, is a stop disc I11.

In the arrangement shown in Fig. 5, the movement of the tape is controlled directly and mechanically by the line coil structure I12. Line coil I12, during its vertical reciprocation, acts through a stud I18 to rock a bell crank latch member I19 which is biased by a spring I8I in a counterclockwise direction (as viewed in Fig. 5).

Latch I19 cooperates with one arm of a three armed lever I82. Arm I83 of lever I32 cooperates with the projection portion of disc H1, to hold the disc I11 against rotation in a counterclockwise direction. Linecoil I12 in response to a marking signal rises to bring the platen I14 into cooperation with the recording wheel I15 and, in so doing, actuates through stud I18, the bell c ank I19 clockwise against the action of its spring I8I, thereby unlatching the lever I82, which responds to the pull ofits spring I84 to disengage arm I83 from the disc I11, thus permitting rotation of the disc I11, which controls through an obvious gear train, the initiation of the movement of the printing tape I18. As the lever I82 is actuated by the spring I84, its arm I85 is brought against the periphery of the disc I11, and after the disc I11 has rotated a few degrees, its projection acts upon the arm I85 to rotate the lever I82 in a clockwise direction against the action of its spring I84 to restore the lever I82 into latching engagement with the latch lever I19, thereby bringing the arm I83 into the path-of the projection on disc I11. If at or before the time the projection on disc I11 reaches the arm I83, a marking signal is impressed on the winding of line coil I12, the lever an arrangement is shown in which a gas filled electronic tube is substituted for the double Winding'relays I23 and I55, in Figs. 3 and 4,

' respectively. The tube used is of the trigger Stop disc I66 after 7 type, in which, if the grid becomes sufficiently positive with respect to the cathode, plate current will begin to flow and will thereafter be independent of grid voltage. The flow of current in this type of tube can only be stopped by opening the plate circuit (or otherwise reducing the plate voltage). the signals are directed over the conductor I9I, then through the line coil I92 to ground. The grid I93 of electronic tube I94 is connected in parallel with the line coil I92. The plate' I95 of the tube I94 is connected to the winding of a magnet I96. The circuit for magnet "I96 extends from battery I91 through the tube I94, thence through the winding of magnet I96, over conductor I98, through contact I99, then back to battery I91. Accordingly, when marking signals are received over the line -I9I, the line coil I92 will be actuated upwardly to effect printing, and since the flow of current through the 1 inting coil causes a voltage drop across the line coil I92, thus voltage is impressed across the tube grid and cathode which are connected in parallel with the line coil I92, thus tripping the tube and allowing plate current to flow continuously thereafter through the circuit previously described for the magnet I96, causing magnet I96 to become energized until interrupted by opening of contact I99. Upon ener- I Referring to Fig. 6,

a wax coated tape, by means of sparking or arcing from a free running spiral member 2!! near the tape 2i6 but out of contact. With this arrangement, signals are transmitted from the transmitter over the conductor 2", through the contact 201, through the primary winding III of transformer 208, over conductor 2, to

negative battery. Transformer 2", in the present embodiment, is shown as a step-up transformer with an interrupter or vibrator in the primary; The vibrations caused in the vibrator of transfomer 209 generate higher voltage in the circuit including'the secondary winding 2, the contact 2|! and 2H, and the recording wheel Iii. High voltage is necessary to break down the resistance of the air gaps: between the knife edges and scanning wheel'iii. The arcing or sparking thus produced between the contact Ill andthe recording wheel 215, causes a record to be made or impressed on the chemically prepared tape 2l6 interposed between the contact I and the wheel 2|, without requiring pressure as in the structures of Figs. 3, 4, and 5, and requiring a minimum of power to rotate the spiral printing member.

While the invention has been described and disclosed with regard to a particular type of apparatus, it is manifest that various departures may be made from the disclosure without departing from the spirit and scope of the invention.

What is claimed is:

i. In a telegraph system, a transmitting element and a receiving element rotatable s'ynchronously, record reading means for controlling I signal transmission, receiver tape feeding means,

means for stopping said tape feeding means automatically upon cessation of signal transmission, and means effective independently of said record reading means ioninserting a start signal invariably upon the resumption of signal transmission to insure that tape feeding starts in the receiver when the transmitter is started.

2. In a telegraph system, a signal channel, a record reader, means operable under the control of said record reader for transmitting over said signal channel groups of signals in successivecycles, each cycle corresponding to the light and dark areas of a scanned character, means effective independently of said record reader for transmitting over said signal channel a tape start condition, in combination with a receiver connected to said channel and provided with a printing mechanism responsive to received signals over said channel to record the transmitted character, tape feeding mechanism at said receiver, and means responsive to said start condition to control said tape feeding mechanism.

3. In a telegraph system, a record reader for controlling the transmission of a series of individual symbols, physical embodiments of each of said symbols, a signal channel, a signal generating scanning device connected to said channel, means controlled by said record reader to operatively associate any one of said embodiments of symbols with said scanning device,

v certain of said embodiments effective independently of said recordreader to transmit a control impulse, a recording device connected to said channel, and means in said recording device effective under the control of said control impulse for controlling the movement of a recording medium through said recording device.

4. In a telegraph system, a signal channel, a series of character members, a scanning device connected to said channel, means controlled by a record tape to operatively associate any character member with said scanning device, electrical circuit means effective under certain operating conditions to initiate the operation of said scanning device, and means controlled by said circuit means to automatically prevent the operation of the scanning device when the tape has become taut.

5. In a telegraph system, a signal channel, a seriesof character members, a scanning device connected to said channel, means effective under the control of a controlling medium to operatively associate any character member with said scanning device, electrical circuit means effective under certain operating conditions to initiate the operation of said scanning device, and means controlled by said circuit means to automatically prevent the operation ofv the scanning device when said medium becomes taut.

6. In a telegraph system, a signal channel, a series of character members, a scanning device connected to said channel, means eifective in response to a control strip to operatively associate any character member with said scanning device, a recording device responsive to said association, electrical circuit means effective under certain operating conditions to start said scanning device into operation, means responsive to said scanning device under the control of said strip to control a recording medium in said recording device, and means controlled by said circuit means to automatically prevent the operation of both said devices when said control strip becomes taut.

7. In a telegraph system, a signal channel, a series of constantly rotatable symbols, a scanning device, sensing means controlled by a record tape for controlling the scanning of any one of said symbols by said device, electrical circuit means effective under certain operating conditions for initiating operation of said tape sensing means, and means controlled by said circuit means to automatically prevent the operation of said tape sensing means in response to a taut condition of the tape.

8. In a telegraph system, a signal channel, means to transmit over said channel a group of signals individual to each character which are composed of a plurality of scanning lines,

means to transmit a single starting signal pre-' ceding each series of groups of character signals, a recorder, normally inert tape feed mechanism at said recorder, and means controlled by a signal generated'by said second recited means to initiate the operation of said tape feed mechanism.

9. In a telegraph system, a tape controlled I lever when in operating position, and a latch engaging said lever and restraining said lever in operating position, said latch responsive to the tape in taut condition to unlatch said lever to interrupt said circuit to stop said transmitter.

10. In a telegraph system, a tape controlled transmitter, a lever efiective to start said transmitter into operation upon manual operation, and a latch engaging said lever and effective to restrain said lever in operated position to maintain said transmitter in operation, said latch responsive to the tape becoming taut to release said lever to stop said transmitter.

11. In a telegraph system, a tape controlled transmitter, manual means to start said transmitter, a latch for said manual means, and tape controlled means to operate said latch to unlatch said manual means.

-12. In a printing telegraph system, a tapedriving mechanism, starting means for said tapedriving mechanism, including a self-holding circuit, a circuit including a winding of a relay responsive to a line signal for closing said selfholding circuit, and means operable by said tapedriving means after leaving stop position for interrupting said self-holding circuit.

13. In aprinting telegraph system, a tapedriving mechanism, trigger means responsive to a line signal for starting said tape-driving mechanism, and means operable by said tape-driving means after leaving stop position for resetting said trigger means.

14. In a printing telegraph system, a tapedriving mechanism, trigger means including a gas filled electronic trigger valve responsive to a line signal for starting said tape-driving mechanism, and means operable by said tape-driving means after leaving stop position for resetting said trigger means.

15. In a printing telegraph syystem, a plurality of transmitting elements representing severally the several characters to be transmitted, an additional transmitting element, a manual switch, means responsive to said manual switch to qualify said additional transmitting element to transmit a control signal, and further means responsive to said first mentioned means to qualify subsequently ones oi. said first mentioned transmitting elements to transmit printing signals.

16. A telegraph transmitter including a mechanism for sensing control indicia on a control strip, a plurality of transmitting elements each having a series of spaced contact segments representative of light and dark areas of a scanned character, means cooperative with said elements for transmission of corresponding impulses, a plurality of permutation bars, means controlled by said permutation bars for controlling the seing combinations to select the cooperative means,

and means responsive to a condition of the control strip for precluding the operation of said indicia sensing mechanism.

17. A telegraph transmitter including a mechanism for sensing control indicia on a control strip, a plurality of transmitting elements each having a series of spaced contact segments representative of light and dark areas of a scanned character, means cooperative with said elements for transmission of corresponding impulses, a plurality of permutation bars, means controlled by said permutation bars for controlling the selection and operation of said cooperative means, means controlled by the indicia sensing mechanism for setting said permutation bars in varying combinations to select the cooperative means, mean responsive to a condition of the control strip for precluding the operation of said indicia sensing mechanism, and manually operative means effective following the operation of said last-mentioned means for establishing a condition whereby said indicial sensing mechanism may be operated and to operate one of said permutation bars to control the transmission of a start signal.

18. A telegraph transmitter including mechanism for sensing control indicia on a control strip, a plurality of transmitting elements one identified with each element of a permutation code, means cooperative with said elements for nism for sensing control indicia on a control strip, a plurality of transmitting elements one identified with each element of a permutation code, means cooperative with said elements for transmission of corresponding impulses, an electromagnet in said indicia sensing mechanism.

means responsive to a condition oi the control strip for energizing said electromagnet to pre-. clude the operation of the indicia sensing mechanism, and manually operative means effective following the operation of said last-mentioned means for establishing a condition whereby said electromagnet is ole-energized and said indicia sensing mechanism may be operated under the control of said control strip.

RAYMOND E. ZENNER. 

